Conventionally known as means for selecting eyeglass lenses are methods which utilize eyeball models. As the eyeball models, well known are the Gullstrand eyeball model and the Le-Grand eyeball model.
These eyeball models have been used entirely for the design and evaluation of eyeglass lenses. For the design of eyeglass lenses, one standard model prepared as an optical eye model would make it possible to design lenses having various powers for standard eyes. This is sufficiently enough for the design irrespective of the eye structure of a person because he/she can select among eyeglass lenses prepared every power of 0.25 D by actually wearing them, thereby ensuring that he/she finds eyeglass lenses suitable for correction. That is, there is a flexibility of selection.
These days, on the other hand, to measure uncorrected or corrected vision, one goes to see an ophthalmologist or has his/her sharpness of vision measured at eyeglass shops using their optometers.
Recently, for example, virtual malls are available over networks such as the Internet; however, any of the eyeglass shops available in these virtual malls provides no system for measuring the uncorrected and corrected vision on an on-line basis.
However, to solely determine the power of eyeglass lenses suitable for the eyes of an individual, an optical eyeball model such as the eyeball model assumed to be commonly applicable to everyone would cause significant error in optical calculation thereby making the determination impossible. The determination can be made only by constructing an optical eyeball model for each person.
Using the conventional eyeball models, as they are, will raise the following problems. That is,                Since the conventional eyeball model is based on measurements made on eyes of people from Europe and the United States, they cannot be used for constructing a model having values close to those obtained by measuring living eyes of other races, e.g., Japanese people. For example, Japanese have a smaller radius of curvature of the cornea than do people from Europe and the United States.        A model is prepared based on an average of measurements.        
Literatures show such data that the depth of the anterior chamber of the eye varies with age or the length of the eye axis is correlated with the degree of myopia for low degrees of nearsightedness. Thus, it is apparently necessary to construct an optical eyeball model according to the age and the degree of myopia of each individual.                Although the lens of the eye has a refractive index unevenly distributed, the average refractive index is used. The simplified double structure provided to the lens of the eye causes a significant error in tracking rays of light.        
On the other hand, where difficulty is found in visiting medical care providers or eyeglass shops such as due to the time required and the distance traveled for the visit, there has been a need for implementing a system which enables one to remotely measure his/her sharpness of vision over the Internet.
In particular, one's currently wearing eyeglasses or contact lenses may provide more blurred viewing than before. In this case, it would be very convenient if one can remotely measure his/her uncorrected and corrected vision in order to determine whether he/she needs to buy new eyeglasses or contact lenses.
It is therefore a principal object of the present invention to provide a system and method for determining an eyeglass/contact lens power suitable for an individual.